Shock absorbing landing gear



",.`Sept.2,19'417. H. s. BEAN ifm. 2,426,585

sHocx Agonms LANDING GEARy Filed Jan. 1 5', 194e 3 sheets-sheet 1 22 .fINVENToRs HOWARD S. BEAN BY WIS G. MORE Y I ATTnPNrv Sept. 2, 1947. H.SBEAN ET A1.

SHOCK AB'SORBING LANDING GER Filed Jan. 15, 1946 l Sheets-Sheet 2-spt.2,1947. H, s., BEAN UAL 2,426,585

SHOCK ABSORBING LANDING GEAR j Filed Jan. 15, 194e s sheets-sheet s A \5F/G.6. 70 I Fla? l 2 Il. J 60.

I4 w E 27 l 'ff 55 l i l l i v -INvENToRs l A HOWARD s. BEAN .4f BYFRANC/S G MHEY fQ/fw 23 A ATTORNEY Patented Sept. 2, 1947 2,426,585SHOCK ABSORBING LANDING GEAR Howard S. Bean and Francis C. AMorey,Kensington, Md., assignors to United States of America, as representedby the Secretary of the Navy Application January 15, 1946, Serial No.641,3.61

2 Claims. (Cl. 244-138) (Granteannaer the act of March 8, 1883, asamended April so, 1928; 870 o. G. 757) This invention relates to landinggear for aircraft and particularly to improved means adapted tofacilitate the safe landing of parachute-borne aircraft components orcargoes.

An important object of the invention is to provide an improved landinggear of the character indicated which is very light, simple and compactin construction, of rugged character and accordingly not apt to get outof order, and which is of oriiices, the diameter and positioning ofwhich are such that a iiuid, which must be forced therethrough duringthe landing operation, is permitted to pass at a controlled rate whicheffectively and gradually absorbs the shock of landing over a relativelyconsiderable period of time.

Another object of the invention is toprovide an improved landing gear ofthe type indicated having shock absorbing elements provided withcollapsible foot portions so mounted and arranged as to impose theminimum parasitic air resistance and which automatically open when thelanding gear is brought into operation, to provi-de a large andeffective area of ground contact.

Other objects and advantages will become apparent during the course ofthe following description, taken in conjunction with the drawingsforming a part hereof,` throughout the several views of which likereference characters designate equivalent parts.

In the drawings:V

Figure 1 is a fragmentary perspective view of the fuselage of a gliderprovided with landing gear incorporating the principles of our presentinvention, showing the landing gear installed and, retracted, a portionof the fuselage being broken away to -aiford a better view of thelanding gear assembly.

Figure 2 is a similar-perspective view from besectional view of theshock absorber mechanism with the parts in retracted position.

Figure 4 is a view partly in substantially diametrlc longitudinalsection and partly in side elevation of the reservoir for hydraulicfluid which forms a part of and is connected to the shock absorbermechanism.

Figure 5 is a sectional elevational View, partly broken away, takensubstantially on the line 5-5 of Figure 3 and looking in the directionof the arrows.

Figure 6 is a central vertical sectional View similar to Figure 3, buton a smaller scale, showing the parts extended, portions being brokenaway.

Figures '1, 8 and 9 are cross-sectional views taken substantially on thelines 1-1, 8--8 and 9 9 respectively of Figure 3 and looking in thedirection of the arrows.

The drawings illustrate a single complete shock absorbing landingdevice, although it will be understood that a plurality of these may beused upon the item-gear or craft to be landed, the rate of descent ofwhich prior to landing will be controlled by a parachute (not shown).

' As shown in Figures 1 and 2, the unit is in- Y stalled insubstantially vertical position, with a low but showing the landing gearprojected and landing foot portion 2U depending from the body to belanded. The body to be landed is fragmentarily illustrated as a gliderfuselage, designated L. The main cylinder l is bracketed at I8 to abulkhead I9 of the fuselage- The lower end of the cylinder, whichprojects slightly below the fuselage, is provided with an annular head 2screwed in place and through which the combined piston and rod assembly4 slides. The upper cylinder head 5 is also of annular form and retainsan axially disposed metering tube 1 which projects into the cylinder. Agasket 1a may be disposed between the cylinder and the head. rIhe pistonportion 4 is longitudinally bored as indicated at 8 to receive themetering tube 1. The piston packing ll is retained by an annularretaining element I0 which has a snug sliding fit with the meteringtube. Attached te the head as by means of a connecting nipple l2 screwedinto the upper end thereof is a reservoir I4 for the hydraulic fluid.The hydraulic fluid may consist of equal parts of alcohol and castoroil. The reservoir, best shown in Figure 4, is provided at its upper endwith a filler plug 41 and a ball check valve 48. The valve ball permitsentry of air When the piston drops and escape of air when the reservoiris being lled, but closes in event of inverting of the aircraft orcargo, to prevent escape of the iluid. Batlle plates I5, It Within thereservoir break up the jet of fluid issuing from the metering tube 'I asthe piston 4 is forced into the cylinder I.

Mounted upon the reduced. lower extremity 4a of the piston and rodassembly 4 is a,crowf'oot landing element generally designated 20consisting of a pair of transverse arms centrally pivoted Y upon the rodsection 4a, and swingable from an inactive position in which they lieparallel to one another, to a crossed operative position in whichr theyextend transversally with respectto one' an'- other. Each such rotatablefoot section includes a hub 23 and a pair of tubular arms 21 22 weldedYto and projecting radially from the hub, as best shown in Figures 1 and2. A torsion spring 54, wrapped about the adjacent hub portions 23 ofthe two foot assemblies rea-cts in oppositev angular directions againstsuch. foot portions, tending to swing them to perpendicular position,their rotary movement underthe influence of the spring being limited bya check chain 52. When the piston rod assembly is in the raised,retracted `position of iiight, show-n in. Fig. 1, the crow-foot portionsare held in parallel relation by a U-bracket 50, from which the footportion is automatically freed as it is lowered to operative position,allowing Vthe foot portions to immediately swing tov their crossed,operative relationship as shown in Fig. 2. Where the gear is used upon aglider the foot portions when retracted are preferably helbl-V by thebracket i) in' parallel relation tothe line of flight. p

During night the piston and connected footassembly are held in raisedposition by means oi a laterally slidablel detent pin 2l projectedthrough the side of the cylinder into'engagement with a peripheral slot28 inthe piston Wall. The detent pin projects slidably through a smallcylinder 55 attachedI to the side of cylinder I, a piston 5T beingcarried by the pin within cylinder 55. A small releasecylinder i'attached tothe side of cylinder 55l houses anv electrically operablesquib or primer and communicates interiorly with the cylinder 55 uponthe Yside ofV piston 51 nearest the large cylinder I'. Thel detent pinl21 is normally maintained in its projected, lockingposition inengagement with the slot 28 by means of a shear wire 55.

When the squibv is fired, the piston 51 is forced back, shearing wire 59and freeing the detent from the piston assembly, which then falls undergravity to the extended position of Fig. 2, the crow-foot portionsmoving to their crossed rela'- tionsh-ip as soonI as released from thebracket 5U. Air enters the reservoir I4 through the check valve 43yduring .such extension. The metering tubeA is provided with a pluralityof metering orifices selectively sized and positioned to provide desiredcushioning characteristics upon landing. As the gear is projected duringthe descent, hydraulic fluid lters through the metering orifices,filling the space between the metering tube and cylinder I. When thefoot assembly strikes. the ground, and the cylinder is forced downwardlyover the piston assembly, the hydraulic fluid is forced out of the spacebetween the metering tube and cylinder I and back into the reservoirthrough the metering orifices, which thus control-the rate of telescopicmovement and therefore the rate of descent of the load.

The invention herein described may be manufactured and used by or forthe Government of the Unitedy Statesof America for governmentalpurposes-'without the payment of royalties thereon or therefor.

We claim:

1. A landing gear for parachute-borne loads, comprising a bufferassembly, a rod connected to. thev buffer assembly and controlled in itsrate of movement thereby, a ground-engaging foot assembly' carried bysaid' rod, said foot assembly comprising a pluralityv of foot, portionsswingable around the longitudinal axis of they rod in a plane:substantially perpendicular thereto, means tendingto swing said portionsto a diverging operative position, and means for holding said portionsinan inoperative position at desired times.

2'.V A landing gea-r'- for parachute-borne loads, comprising a buffer'assembly, a rod connected to the buier' assembly and controlled in itsrate of movement thereby, said rod also being movable from a retractedposition to a projected operative position independently of the bufflngaction, a plurality of' foot portions swingable around the longitudinalaxis of thev rod in a plane substantially perpendicular thereto, meansfor holding 'said foot portionsv in an inoperative position when saidlrod is retracted", means for releasing said foot portions and forswing-ing the same to .operative diverg-ing positions when said rod isprojected.

HOWARD Si. BEAN.v FRANCIS C. MOREY.

REFERENCES CITED The following references Yare of record in the file ofthis patent:

297,202 Great Britain Sept. 20 1928

